Salesforce Bulk API Starter – Started by me in 2014, this project contains C# code for getting started with the Salesforce Bulk API. The test project contains test methods that demonstrates how to Query, Insert, Upsert, and Delete records using the Salesforce Bulk API. Please note that this is starter code and doesn’t include error handling, validation logic, and other expected regular software features. If you’ve found this useful, please let me know on Twitter. Nuget Download
Salesforce Boostr – 
Boostr Chrome extension for Salesforce.com. Started by mattsimonis in February, 2016, this extension provides various useful enhancements to the Salesforce UI when logged in. Examples include clearing out the text in the Admin Search’s textbox and showing the number of fields selected on the field history tracking page. Salesforce Boostr Chrome Extension Link
Sudoku Solver – This is a C# library that showcases how to solve an NxN Sudoku puzzle using various algorithms. It can solve any puzzle on WebSudoku.com. See the test project for how to use the library to solve puzzles. Clone the repository and try adding your own algorithms.